Blood is always a liquid in short supply and large amounts of blood are used during blood transfusions, e.g. in connection with surgical operations. Blood is expensive to collect, to test as well as to store. There is also a risk of transmission of jaundice, HIV-infection and other diseases during blood transfusions.
In connection with certain operations the patient may lose large quantities of blood, sometimes as much as several liters. This blood normally is wasted and the patient has to receive the corresponding amount of blood through transfusions.
The problem of supplying blood has to some extent been solved in various ways. There are e.g. methods of purifying and anticoagulation-treating blood, which has been partially coagulated, but these methods are expensive and time-consuming, and the transfusion product is inferior. Also. autotransfusions are used now, a patient letting his own blood as a blood-donor a few weeks before a planned operation, the patient, in case a need arises, having his own blood restored during or subsequent to the operation. However, this method needs planning and cannot be applied when emergency operations are needed. Normally, the patient also must be reasonably healthy, when he is a blood-donor, and equipment for possible purification, catalogueing and storage of the patient's blood is required. This method has so far only been sparingly used.
Consequently, the basis of the invention, according to the last mentioned aspects of blood treatment, has been the idea of trying to collect and autologously inject in the patient as much as possible of his own blood, which is removed from his blood vessel system during the operation.
Four main problems arise when doing this:
When blood is sucked from a wound surface, large amounts of air or another gas or a gas mixture inevitably are sucked jointly with the blood, which results in an air admixture with a strong frothing, which like the contact of the blood with foreign substances and free air contributes to an initiation of the mechanisms, which lead to an activation of the coagulation system of the blood as well as alterations of or in the cells of the blood; PA1 When blood is stored in some type of storage unit, air or another present gas as well as froth will be dominant in the storage unit, which accelerates the coagulation and besides prevents a direct return of the blood to the patient, partly due to the air contents itself and partly also due to the fact that the enzyme system and the cells of the blood are activated by the interface between blood and air bubbles; PA1 The collected material may contain not desirable tissue fragments from the operation wound (clots, muscle, fat, bone etc.), which activate the enzyme system of the blood; this activation as well as the admixture of not desirable and in this connection dangerous tissue fragments prevent a direct return of the collected blood to the patient; and PA1 The collected blood may be infected and consequently it will be clearly inappropriate to return the blood in this condition to the patient. PA1 The blood which disappears during the surgical operation is sucked continuously; PA1 The sucked blood/air/gas-mixture receives automatically and in proportion to the amount of sucked blood an admixture of an anticoagulant agent, e.g. a citrate of a type which is active and known per se, of a disinfectant or of any type of blood preserving agent, controlled by a differentiated pressure in the system; PA1 The blood/air/gas mixture is caused, in a closed system, to pass a defoaming and separation filter, in which the blood froth is disintegrated and not desirable particles are separated, whereas the blood is allowed to pass; PA1 The blood flows into a receiver, in which the blood is allowed to slowly flow downwards along the walls of the receiver or along inclined planes mounted in the receiver, whereas air bubbles included in the blood are allowed to escape to the upper part of the receiver; PA1 The blood is collected in the lower part of the receiver, which in its bottom is provided with a valve, which opens up when a certain amount of blood has been collected in the bottom of the receiver, the blood flowing into a collecting vessel, said valve closing again when the blood level in the lower part of the receiver has been lowered to such an extent, that there may be a risk that air and gas will follow the blood into the collecting vessel; and PA1 The collection of the blood in the vessel is done entirely without any admixture of air or any other gas by means of a certain negative pressure, which acts on a completely air-void flexible container, and the suction of air from the upper part of the receiver is done by means of a suction system with a negative pressure, which is higher (more negative) than the pressure on the flexible collecting container and the pressure on a container for the anticoagulant.